High
Security advisory
A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values `cursor->header.width` and `cursor->header.height` can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-4207
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 06:20 UTC · Revision 1
Source evidence
A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values `cursor->header.width` and `cursor->header.height` can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.
osv:CVE-2021-4207
Complete source record
{
"id": "40186fda987d599c91486d49cd922a23989924b1e8d427886c1f1316efce372e",
"url": "https://osv.dev/vulnerability/CVE-2021-4207",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-4207",
"summary": "A flaw was found in the QXL display device emulation in QEMU. A double fetch of guest controlled values `cursor->header.width` and `cursor->header.height` can lead to the allocation of a small cursor object followed by a subsequent heap-based buffer overflow. A malicious privileged guest user could use this flaw to crash the QEMU process on the host or potentially execute arbitrary code within the context of the QEMU process.",
"evidence": "osv:CVE-2021-4207",
"products": [],
"severity": "high",
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"modified": "2026-10-24T10:30:37.987701310Z",
"provider": "osv",
"references": [
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"https://security.gentoo.org/glsa/202208-27",
"https://security.netapp.com/advisory/ntap-20250321-0009/",
"https://www.debian.org/security/2022/dsa-5133",
"https://bugzilla.redhat.com/show_bug.cgi?id=2036966",
"https://starlabs.sg/advisories/21-4207/"
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},
"source_id": "core-osv",
"document_id": 434346,
"published_at": "2022-04-29T17:15:20.1+00:00"
}